Originally, the various devices provided in a vehicle, in particular a motor vehicle, were operated via separate control elements. For example, there were rotary switches for adjusting the airflow and the temperature, switches for adjusting the various ventilation nozzles, switches for controlling the lighting devices for the interior of the vehicle, and control elements for a radio or CD player. Since then, in modern motor vehicles, so many devices are now provided for adjusting various vehicle functions, information systems, driver assistance systems and entertainment systems, that it is no longer expedient to provide separate control elements for all the vehicle devices. For this reason, the wide range of vehicle devices are controlled by means of a standard control concept with a small number of control elements which are operated in conjunction with a graphical user interface. In this case, the display apparatus displays switching areas which can be selected by the control element. For display purposes, the display apparatus may comprise a display, in which case, in a general form, a display means an apparatus for usual signaling of different information items. Normally, various forms of liquid crystal displays are used as the display. The display on the display apparatus can visually provide the driver with traffic-related or operation-related data for the vehicle. Furthermore, it can assist the driver in navigation, or in communication with the outside world. A so-called combination instrument is for this purpose arranged in the vicinity of the primary field of view of the driver. Normally, it is located in the dashboard behind the steering wheel, in which case it can be seen through an opening in the steering wheel. It is used in particular to display the speed, the fuel contents, the radiator temperature and other operation-related information items relating to the motor vehicle. Furthermore, radio and other audio functions can be displayed. Finally, menus can be displayed for telephone, navigation, telematics services and multimedia applications. The display furthermore assists the control of various further devices in the vehicle.
In addition to the combination instrument, a display apparatus is often arranged above the center console of the vehicle, via which further information items can be displayed. In particular, this display apparatus is used as a multifunction display and to display a geographic map from a navigation system. One such multifunction display is described, for example, in DE 199 41 956 A1.
The multifunction displays are operated in conjunction with a control system which may comprise various control elements. For example, a plurality of selection and function keys for controlling the vehicle devices are provided in DE 199 41 956 A1. On the other hand, DE 199 41 960 A1 describes a multifunction control element for selection of function groups and individual functions, which comprises a cylinder which can be rotated in both directions and can furthermore be moved at right angles to the rotation axis. EP 1 026 041 A2 describes a multifunction control unit for a motor vehicle. The control unit comprises a display and a function strip with function keys, which have fixed purposes, such as radio, on-board computer, telephone, navigation unit. When the function keys are operated, the display is assigned to the appropriate appliance, and the appliance causes its current operating status to be displayed on the display. Furthermore, freely programmable function keys are provided, possibly as well as function keys with a macro-command capability. These keys may be assigned by free programming to an appliance in the vehicle, which causes its respective operating status to be displayed on the display when the appropriate function key is operated.
Furthermore, DE 35 14 438 C1 discloses a central control input and information output for controlling a plurality of accessories which are installed in a vehicle. The input and output apparatus comprises a display unit and control keys which are unambiguously associated with the elements in the displayed menus. The elements in the menus indicate functions which can be initiated by the respective control keys. Menus for individual accessories can be selected via a basic menu, which can be displayed on the display. Furthermore, the system comprises additional control elements, by means of which specific basic functions of the central control input and information output, and accessories can be accessed at any time and independently of the instantaneously selected menu.
In addition to the stated control elements described above, it is also being proposed that the display itself be equipped with a touch-sensitive surface, thus providing a so-called touchscreen in this way. In the case of a touch screen such as this, the control action is carried out by the user using his fingertip, for example to touch the touchscreen. The position of the touch is detected, evaluated and associated with a control step. In order to assist the user in the control process, virtual switches can be displayed as graphical switching areas on the display. A display apparatus having a touch-sensitive surface which is used in conjunction with a navigation system is described, for example, in DE 10 2005 020 155 A1.
The display of information in a vehicle and the control of the wide range of devices in the vehicle are subject to very specific requirements. The information perception and control process are carried out in the vehicle inter alia by the driver. The information items should therefore be displayed in the vehicle such that the information perceived by the driver does not distract him while driving. The displayed information should therefore be detectable intuitively and quickly by the driver, in such a way that he has to divert his view away from the driving situation for only a very short time in order to perceive information. In the same way, it should be possible to control the vehicle devices as easily and intuitively as possible, thus allowing the driver to operate the devices even while driving. If the control process is assisted or guided by a display, the display should be produced such that the drive has to view the display only very briefly in order to carry out the control process.
In order to display the wide range of control and display operations clearly, hierarchical memory structures are frequently used. A menu shows various list entries or objects, and possibly graphics, graphical switching areas or icons associated with the list entries or objects. When a list entry or object is selected, a submenu is opened, with further list entries or objects. This structure can be continued through a plurality of hierarchy levels. Furthermore, a list entry or object can be associated with a specific display content rather than with a submenu, which display content represents the information associated with that list entry or object.
When using hierarchical menu structures in a vehicle, one problem that arises is that the navigation within these menu structures can lead to a driver being distracted. It is, therefore, desirable to develop control concepts for hierarchical menu structures, in which the navigation within the menu structure can be carried out quickly and intuitively by the driver.